Brakes disks for disk brakes, especially in high-performance vehicles, are made with perforation holes in the friction surfaces (outer cover surfaces) of the cylindrical ring-shaped brake disks. In the case of solid brake disks the holes conventionally extend through the entire disk thickness, in the case of internally ventilated brake disks they can also extend only from the friction surface to the inner cavity. The advantage of these perforation holes is improved cooling and more rapid breakdown of the moisture film present when friction surface are wet compared to unperforated brake disk (rings). Another advantage of perforated brake disk (rings) is the cleaning effect of the perforation holes for the friction coating applied to the brake shoes. Wear particles are at least partially removed through the perforation holes, and by the shearing and peeling action of the edges of the perforation holes a “cleaner” friction lining surface without deposits of wear and similar particles is produced.
Compared to unperforated brake disk (rings) this also leads to constant friction behavior under high stresses.
Within the context of this application brake disk (ring) refers to a brake disk ring or a brake disk which encompasses the brake disk ring. In this connection, an integral brake disk is also regarded as encompassing a brake disk ring.
DE 29 01 349 A discloses a metallic brake disk with reduced tendency to squealing and improved heat dissipation, in the friction surfaces of which openings are formed which have different distances from one another in the peripheral direction. In this connection, the openings as shown in the drawings are made only in the area traversed by the brake shoes which are provided with friction linings (brake linings) and are referred to as “brake bodies”.
German Utility Model DE 74 41 560 relates to a disk brake with perforated brake disk for two-wheeled vehicles, the perforation being designed to preclude the adverse effect of water having reached the brake disk on the braking action. Here rows of holes are located within the ring surface traversed by the friction linings of the brake shoes.
German Utility Model DE 70 11 084 likewise describes a brake disk with openings which partially or completely penetrate the brake disk, the openings being located in the parts of the friction surface which come into frictional engagement with the friction linings of the brake.
Published Patent Application DE 22 57 176 A describes internally ventilated disk brakes which comprise two disks which run with a parallel distance, these disks being connected to cross ribs, and openings running in the brake surface in the vicinity of the cross ribs. The openings are made conical, the smaller diameter being on the friction surface side of the disks.
U.S. Pat. No. 5,501,306 discloses a brake disk which contains a brake ring with a plurality of openings or holes, these openings or holes always being located along a radius in the brake ring. The brake ring is solid except for holes (“a solid brake ring”), that is, it particularly does not have any cooling channels within. The purpose of making the holes is to reduce the weight of the brake disk.
U.S. Pat. No. 6,279,697 B1 discloses a brake disk having a surface which acts as a friction surface which is structured by nondirectional indentations which are produced by electrical discharges and the resulting vaporization of metal at the respective locations. In this instance as well, brake disks which are otherwise solid are also machined in this way. The directional (radially or concentrically to the periphery) structures produced by surface machining on the friction surface generate noise during the braking process or lead to increased wear of the brake linings.
Finally, German Published Patent Application 101 57 995 A1 discloses a brake disk of a fiber-reinforced material with perforation holes and radial or involute-shaped cooling channels. The perforation holes promote cooling of the brake disk and improve wet response behavior of the brakes, since water and the water vapor which forms during braking can escape from the surface of the brake disk through the perforation holes.